Polymer compositions containing aliphatic esters as plasticisers

ABSTRACT

This invention relates to the use of a composition of aliphatic esters having the following general formula: 
       R 1 —O—C(O)—R 4 —C(O)—[—O—R 2 —O—C(O)—R 5 —C(O)—] m —O—R 3  
 
     in which:
         R 1  is selected from one or more of the groups consisting of H, linear and branched saturated and unsaturated alkyl residues of the C 1 -C 24  type, and polyol residues esterified with C 1 -C 24  monocarboxylic acids;   R 2  comprises —CH 2 —C(CH 3 ) 2 —CH 2 — and C 2 -C 8  alkylene groups, and comprises at least 50% in moles of the said —CH 2 —C(CH 3 ) 2 —CH 2 — groups;   R 3  is selected from one or more of the groups consisting of H, linear and branched saturated and unsaturated alkyl residues of the C 1 -C 24  type, and polyol residues esterified with C 1 -C 24  monocarboxylic acids;   R 4  and R 5  comprise one or more C 2 -C 22  alkylenes and comprise at least 50% in moles of C 7  alkylenes;   m lies between 1 and 20,
 
as plasticizers for polymer compositions. These esters are particularly suitable for use as plasticizers for various types of polymers such as for example vinyl polymers of the polyvinyl chloride (PVC) type, thermoplastic elastomers, and hydroxy acid polyesters, for example polyesters of lactic acid.

This invention relates to a family of aliphatic esters which areparticularly suitable for use as plasticizers and thermoplastic polymercompositions comprising them. In particular this invention relates tothe use of a family of aliphatic esters having the following generalformula:

R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃

in which:

-   -   R₁ is selected from one or more of the groups consisting of H,        linear and branched saturated and unsaturated alkyl residues of        the C₁-C₂₄ type, and polyol residues esterified with C₁-C₂₄        monocarboxylic acids;    -   R₂ comprises —CH₂—C(CH₃)₂—CH₂— groups and C₂-C₈ alkylenes, and        comprises at least 50% by moles of said —CH₂—C(CH₃)₂—CH₂—        groups;    -   R₃ is selected from one or more of the groups consisting of H,        linear and branched saturated and unsaturated alkyl residues of        the C₁-C₂₄ type, and polyol residues esterified with C₁-C₂₄        monocarboxylic acids;    -   R₄ and R₅ comprise one or more C₂-C₂₂ alkylenes, preferably        C₂-C₁₁, more preferably C₄-C₉, and comprise at least 50% by        moles of C₇ alkylenes;    -   m is a number between 1-20, preferably 2-10, more preferably        3-7;        as plasticizers in thermoplastic polymer compositions.

These aliphatic esters are particularly suitable for use as plasticizersfor various types of thermoplastic polymers, such as for example vinylpolymers of the polyvinyl chloride (PVC) type, thermoplastic elastomers,for example nitrile rubbers and SBR rubbers, and hydroxy acidpolyesters, for example lactic acid-based polyesters (among others PLA).

As is known, plasticizers are very important additives in the plasticsmaterials sectors which, particularly by reducing the glass transitiontemperature of the polymers, improve many of their properties, above alltheir workability, flexibility, resilience and elasticity. In additionto this, depending upon the chemical structure of the plasticiser andthe nature of the polymer with which it is mixed, they can also help toimprove their insulating properties and adhesiveness.

A typical category of plasticizers for plastics materials are phthalicesters, typically known as “phthalates”. However their use has for along time been the subject of many controversies associated with thepotential effects which such compounds might have on human health. Thechemical industry has therefore been engaged in searching foralternative plasticizers to the phthalates for some time.

In order to be effectively used, a plasticiser must show some propertiessuch as for example complete miscibility with the polymers with which itis being mixed, so it can be stably and uniformly incorporated in themand will not tend to migrate towards the surface of the plasticsmaterial (so-called “exudation”) over time. They must also generallyhave low volatility, possibly be odorless and colourless, resistant tothe action of solvents, heat and light, and must be chemically stable,for example to hydrolysis by environmental moisture or oxygen. Given themultiple properties on which they act, and in the light of the manycharacteristics which it is desirable that they should have, theidentification and development of new plasticizers has therefore beenthe ongoing object of intense research in the plastics materialsindustry.

One object of this invention is therefore to develop a family ofaliphatic esters capable of being used as plasticizers for a widespectrum of polymers and capable of demonstrating performance in usewhich, if not equivalent, is even better than that of the plasticizerscurrently commercially available, for example the phthalates.

In particular, this invention concerns the use of aliphatic estershaving the following formula:

R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃

in which:

-   -   R₁ is selected from one or more of the groups consisting of H,        linear and branched saturated and unsaturated alkyl residues of        the C₁-C₂₄ type, and polyol residues esterified with C₁-C₂₄        monocarboxylic acids;    -   R₂ comprises —CH₂—C(CH₃)₂—CH₂— groups and C₂-C₈ alkylenes, and        comprises at least 50% by moles of said —CH₂—C(CH₃)₂—CH₂—        groups;    -   R₃ is selected from one or more of the groups consisting of H,        linear and branched saturated and unsaturated alkyl residues of        the C₁-C₂₄ type, and polyol residues esterified with C₁-C₂₄        monocarboxylic acids;    -   R₄ and R₅ comprise one or more C₂-C₂₂ alkylenes, preferably        C₂-C₁₁, more preferably C₄-C₉, and comprise at least 50% by        moles of C₇ alkylenes;    -   m is a number between 1-20, preferably 2-10, more preferably        3-7,        as plasticizers in thermoplastic polymer compositions.

This invention also relates to the use of mixtures comprising two ormore of these esters.

When mixed, either individually or as mixtures, with thermoplasticpolymers such as vinyl polymers of the PVC type or thermoplasticelastomers, for example nitrile rubbers and SBR rubbers, these estersare capable of for example ensuring mechanical properties which arewholly equivalent to those of other known commercially availableplasticizers, such as diisononyl phthalate.

The present invention therefore refers also to thermoplastic polymercompositions comprising at least one thermoplastic polymer preferablyselected from chlorinated vinyl polymers, for example PVC, thermoplasticelastomers, for example nitrile rubbers and SBR rubbers, and hydroxyacid polyesters, such as for example polylactic acid (PLA), and at leastone plasticizer comprising one or more aliphatic esters having generalformula:

R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃

in which:

-   -   R₁ is selected from one or more of the groups consisting of H,        linear and branched saturated and unsaturated alkyl residues of        the C₁-C₂₄ type, and polyol residues esterified with C₁-C₂₄        monocarboxylic acids;    -   R₂ comprises —CH₂—C(CH₃)₂—CH₂— groups and C₂-C₈ alkylenes, and        comprises at least 50% by moles of said —CH₂—C(CH₃)₂—CH₂—        groups;    -   R₃ is selected from one or more of the groups consisting of H,        linear and branched saturated and unsaturated alkyl residues of        the C₁-C₂₄ type, and polyol residues esterified with C₁-C₂₄        monocarboxylic acids;    -   R₄ and R₅ comprise one or more C₂-C₂₂ alkylenes, preferably        C₂-C₁₁, more preferably C₄-C₉, and comprise at least 50% by        moles of C₇ alkylenes;    -   m is a number between 1-20, preferably 2-10, more preferably        3-7.

In the aliphatic esters according to this invention R₁ and R₃ areselected independently of each other from one or more of the followinggroups: H, linear and branched saturated and unsaturated alkyl residuesof the C₁-C₂₄ type, or polyol residues esterified with C₁-C₂₄monocarboxylic acids. In a preferred embodiment, R₁ is different from R₃if R₁ is H.

With reference to R₁ and R₃, examples of linear and branched saturatedand unsaturated alkyl residues of the C₁-C₂₄ type are methyl, ethyl,propyl, butyl, pentyl, nonyl, allyl, isopropyl, isobutyl, isopentyl,methylbutyl, methylpentyl and methylethyl residues.

As regards the polyol residues which are reacted with C₁-C₂₄monocarboxylic acids, these derive from polyols comprising one or morehydroxyl groups such as for example 1,2-ethandiol, 1,2-propandiol,1,3-propandiol, 1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol,1,7-heptandiol, 1,8-octandiol, 1,9-nonandiol, 1,10-decandiol,1,11-undecandiol, 1,12-dodecandiol, 1,13-tridecandiol,1,4-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propandiol,dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexandiol,cyclohexanmethandiol, pentaerythritol, glycerol, polyglycerol,trimethylolpropane and their mixtures.

The said polyols are bound to the structure of the aliphatic estersaccording to this invention through one of their hydroxyl groups.

As far as the remaining hydroxyl groups of the polyols are concerned,these are partly or fully esterified with one or more C₁-C₂₄monocarboxylic acids. These C₁-C₂₄ monocarboxylic acids may be of thelinear or branched saturated or unsaturated type and may advantageouslyhave one or more hydroxyl or carbonyl groups in the chain.

Typical examples of C₁-C₂₄ monocarboxylic acids of this type arepelargonic acid, stearic acid, palmitic acid, 9-ketostearic acid,10-ketostearic acid, 9-hydroxystearic acid and 10-hydroxystearic acid.

In a preferred embodiment, at least one of R₁ and/or R₃ comprise,preferably in amount of ≧10% by moles, more preferably ≧20%, even morepreferably ≧25% by moles, with respect to the total amount of R₁ and/orR₃, polyol residues esterified with at least one C₁-C₂₄ monocarboxylicacids selected from the group consisting of stearic acid, palmitic acid,9-ketostearic acid, 10-ketostearic acid and mixtures thereof.

In a particularly preferred embodiment, at least one of R₁ and/or R₃comprise, preferably in amount of ≧5% by moles, more preferably ≧9% bymoles, with respect to the total amount of R₁ and/or R₃, polyol residuesesterified with at least one C₁-C₂₄ monocarboxylic acids selected fromthe group consisting of 9-ketostearic acid, 10-ketostearic acid andmixtures thereof.

It has been discovered that the aliphatic esters according to thepresent invention comprising this kind of R₁ and/or R₃ groups, show, andmaintain over time, reduced values of Storage Modulus (G′) whensubjected to torsional deformations. Reduced values of Storage Modulus(G′) indicate an improved shear stress resistance of the polymercompositions containing them. Polymer compositions with improved shearstress resistance are particularly suitable for manufacturing productssubjected to twisting, bending or folding movements, such as forexamples electric cables and wires.

The composition and structure of the aliphatic esters according to thepresent invention may be determined according to any method known to theskilled person, for example by means of HPLC-MS.

With reference to R₂, this comprises —CH₂—C(CH₃)₂—CH₂— and C₂-C₈alkylene groups, preferably C₂-C₄, and comprises at least 50% in moles,preferably at least 75%, of the said —CH₂—C(CH₃)₂—CH₂— groups. In apreferred embodiment R₂ is the —CH₂—C(CH₃)₂—CH₂— group.

As far as R₄ and R₅ are concerned, these are the same or different andcomprise independently of each other one or more C₂-C₂₂ alkylenes,preferably C₂-C₁₁, more preferably C₄-C₉, and comprise at least 50% bymoles, preferably at least 60%, and more preferably at least 65%, of C₇alkylenes. In a particularly preferred embodiment R₄ and R₅ are both C₇alkylenes.

In the esters according to this invention the —C(O)—R₄—C(O)— and—C(O)—R₅—C(O)— groups advantageously derive from linear C₄-C₂₄ aliphaticdicarboxylic acids, preferably C₄-C₁₃, more preferably C₄-C₁₁ and theirC₁-C₂₄ alkyl esters, preferably C₁-C₄. Examples of the said dicarboxylicacids or their esters are: succinic acid, dimethyl succinate, dibutylsuccinate, glutaric acid, dimethyl glutarate, dibutyl glutarate, adipicacid, dimethyl adipate, dibutyl adipate, pimelic acid, suberic acid,dimethyl suberate, dibutyl suberate, azelaic acid, dimethyl azelate,dibutyl azelate, sebacic acid, dimethyl sebacate, dibutyl sebacate,undecandioic acid, dodecandioic acid, brassylic acid, dimethylbrassylate, dibutyl brassylate.

In one embodiment of this invention the aliphatic esters derive frommixtures comprising at least 50% in moles, preferably more than 60% inmoles and more preferably more than 65% in moles, of azelaic acid andits C₁-C₂₄ esters.

The aliphatic esters according to this invention may be preparedaccording to any of the methods known to those skilled in the art, forexample by means of esterification or transesterification reactions. Inparticular the aliphatic esters according to this invention can beprepared by transesterifying mixtures containing alkyl esters of linearaliphatic dicarboxylic acids with polyols, for example neopentylglycol.Those skilled in the art will be in a position to select suitableconditions for preparation in order to obtain the aliphatic esters withthe desired m values, for example working with stoichiometric quantitiesor with a lesser or greater excess of polyols in comparison with themoles of linear aliphatic dicarboxylic acids. The said esterificationand transesterification reactions are performed under suitabletemperature and pressure conditions, advantageously in the presence ofsuitable catalysts.

Depending upon the —C(O)—R₄—C(O)— and —C(O)—R₅—C(O)— groups in thealiphatic esters, those skilled in the art will be in a position tomodify the composition of the linear aliphatic dicarboxylic acids andtheir mixtures which have to be esterified or transesterified. The saidmixtures may be prepared in any way known to those skilled in the art,for example by mixing all their components together or preparingpreliminary mixtures which will be subsequently mixed. It is alsopossible that mixtures of dicarboxylic acids which are alreadycommercially available or available as by-products may be used as abasis, appropriately modifying their composition subsequently accordingto requirements.

In a preferred embodiment, the mixtures of linear aliphatic dicarboxylicacids are for example obtained as intermediate products or by-productsfrom processes for the oxidation of vegetable oils such as those forexample described in patent applications WO 2008/138892, WO 2011/080296or as an evaporate in the process of preparing the complex oligomerstructures described in patent applications WO 2012/085012 andPCT/EP2013/062588. The linear aliphatic dicarboxylic acid mixturesobtained from the oxidation of sunflower oil and milk thistle oil and ingeneral from vegetable oils having a high oleic acid content, are ofparticular interest and make it possible for example to obtain mixtureshaving a high content of azelaic acid.

In addition to helping make use of renewable resources and preservingresources of fossil origin, use of acid mixtures deriving from theprocesses described above has the further advantage that it makes use ofproducts and process fractions which would otherwise be regarded asby-products and which, in order to be marketed or in any event utilisedindividually, would require complex purification processes.

The aliphatic esters according to this invention are particularlysuitable for use individually or as mixtures as plasticizers for a widespectrum of thermoplastic polymers. Thus this invention also relates tothermoplastic polymer compositions comprising at least one plasticizercomprising one or more of the aliphatic esters described above.

In one embodiment this invention relates to thermoplastic polymercompositions comprising from 10 to 80% by weight of a plasticizercomprising one or more aliphatic esters described above.

As far as the said thermoplastic polymer compositions are concerned,these may include one or more thermoplastic polymers selected fromchlorinated vinyl polymers, for example PVC, thermoplastic elastomers,for example nitrile rubbers and SBR rubbers, and hydroxy acidpolyesters, such as for example polylactic acid (PLA).

Of the chlorinated vinyl polymers, these are here to be understood toinclude, in addition to polyvinyl chloride: polyvinylidene chloride,polyethylene chloride, poly (vinyl chloride-vinyl acetate), poly (vinylchloride-ethylene), poly (vinyl chloride-propylene), poly (vinylchloride-styrene), poly (vinyl chloride-isobutylene) as well ascopolymers in which the polyvinyl chloride represents more than 50% bymoles. The said copolymers may be random, block or alternatingcopolymers. Preferably the polymer compositions comprising one or moreof the said chlorinated vinyl polymers comprise 10 to 80% by weight ofthe aliphatic esters according to this invention.

With regard to the thermoplastic elastomers, these comprise both naturalrubbers (NR) and synthetic rubbers. Examples of synthetic rubbers arerubbers having a diene base such as vinylarene-diene conjugatecopolymers (e.g. SBR, styrene/butadiene rubber), diene polymers (e.g.polybutadiene, isoprene), ethylene-propylene copolymers, in particularethylene/propylene/diene terpolymers (EPDM, ethylene/propylene/dienemonomer) and thermoplastic elastomers such as styrene-butadiene-styrene(SBS) block copolymers, nitrile rubbers, acrylonitrile-butadienecopolymers (NBR) and styrene-isoprene-styrene (SIS) copolymers.

In a preferred embodiment of the invention the elastomers are selectedfrom nitrile rubbers or random conjugate vinylarene-diene copolymers.

Preferably, the polymer compositions comprising one or more of the saidthermoplastic elastomers comprise 5 to 70% by weight of the plasticizercomprising the aliphatic esters according to this invention.

Examples of hydroxy acid polyesters are: poly L-lactic acid, polyD-lactic acid and stereo complex poly D-L lactic acid,poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate,polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate,polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate,polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate,poly 3-hydroxybutyrate-4-hydroxybutyrate. Preferably, the saidpolyesters are those of lactic acid, here also indicated by PLA: polyL-lactic acid, poly D-lactic acid and stereo complex poly D-L-lacticacid and copolymers comprising more than 50% in moles of the said lacticacid polyesters. Preferably the polymer compositions comprising one ormore of the said lactic acid polyesters comprise from 10 to 80% byweight of the plasticizer comprising the aliphatic esters according tothis invention.

The polymer compositions according to this invention, in addition to thealiphatic esters described in this invention, may also comprise otheradditives such as other plasticizers, fillers, biofillers, pigments,nucleating agents, extender oils, separating agents, crosslinkingagents, compatibilising agents, dyes and thermal stabilisers.

Thanks to the plasticising properties of the aliphatic esters accordingto this invention the polymer compositions comprising it may beeffectively used to produce manufactured articles such as lifesavingsurgical drapes, electrical cables, wires, films, synthetic fabrics forclothing and shoes, and components for the motor industry.

In addition to the purposes described above the aliphatic estersaccording to this invention may also find application as modifyingagents for polyesters and polyamides, and as impregnating components forwood and bases for thermohardening and thermoplastic polyurethanes.

The aliphatic esters according to this invention may be added to thepolyesters and polyamides at any stage during their processing, anddepending upon the conditions of addition may act as reactive andnon-reactive modifying agents. When the aliphatic esters according tothis invention are used as reactive modifying agents, effectivequantities of compounds likely to encourage such reactions, such as forexample transesterification catalysts, crosslinking agents, chainextenders and peroxides, may advantageously be added.

As far as polyesters are concerned, these in general here includebiodegradable and non-biodegradable polyesters of the diacid-diol type.The biodegradable polyesters may be either aliphatic oraliphatic-aromatic.

Biodegradable aliphatic polyesters from diacid-diols may comprisealiphatic diacids and aliphatic diols while the biodegradablealiphatic-aromatic polyesters have an aromatic part mainly comprisingaromatic acids with multiple functional groups of both synthetic originand renewable origin, the aliphatic part comprising aliphatic diacidsand aliphatic diols.

The biodegradable aliphatic aromatic polyesters from diacids-diols arepreferably characterised by an aromatic acids content of between 30 and90% by moles, preferably between 45 and 70% by moles with respect to theacid component.

Preferably the aromatic acids having multiple functional groups ofsynthetic origin are dicarboxylic aromatic compounds of the phthalicacid type and their esters, preferably terephthalic acid. The aromaticacids having multiple functional groups of renewable origin arepreferably selected from the group comprising 2,5-furandicarboxylic acidand its esters.

Particularly preferred are biodegradable aliphatic-aromatic polyestersfrom diacids-diols in which the aromatic diacid component comprisesmixtures of aromatic acids having multiple functional groups ofsynthetic and renewable origin.

The aliphatic diacids of biodegradable aliphatic polyesters andaliphatic-aromatic polyesters are aliphatic dicarboxylic acids such asoxalic acid, malonic acid, succinic acid, glutaric acid,2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, undecanoic acid, dodecanoic acid and brassylic acid,their esters and their mixtures. Of these, those preferred are adipicacid and dicarboxylic acids from renewable sources, among these thedicarboxylic acids from renewable sources such as succinic acid, sebacicacid, azelaic acid, undecandioic acid, dodecandioic acid and brassylicacid and their mixtures being particularly preferred.

Examples of aliphatic diols in the biodegradable polyesters fromdiacids-diols are: 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol,1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol, 1,7-heptandiol,1,8-octandiol, 1,9-nonandiol, 1,10-decandiol, 1,11-undecandiol,1,12-dodecandiol, 1,13-tridecandiol, 1,4-cyclohexandimethanol,neopentylglycol, 2-methyl-1,3-propandiol, dianhydrosorbitol,dianhydromannitol, dianhydroiditol, cyclohexandiol, cyclohexanmethandioland their mixtures. Of these 1,4-butandiol, 1,3-propandiol and1,2-ethandiol and their mixtures are particularly preferred.

Preferably the composition of the aliphatic esters according to thisinvention with the biodegradable polyesters from diacid-diols describedabove are characterised by a content of the plasticizer comprising saidaliphatic esters which varies within the range from 0.2 to 20% by weightwith respect to the total weight of the said compositions, preferablybetween 0.5 and 10%.

Among the non-biodegradable polyesters, those preferred are: PET, PBT,PTT and polyalkylene furandicarboxylates. Of the latter, thoseparticularly preferred are polyethylene furandicarboxylate,polypropylene furandicarboxylate, polybutylene furandicarboxylate andtheir mixtures.

Preferably the aliphatic ester compositions according to this inventionwith the non-biodegradable polyesters are characterised by a content ofthe plasticizer comprising said aliphatic esters which varies within therange from 0.2 to 20% by weight with respect to the total weight of thesaid compositions.

Examples of polyamides are: polyamide 6 and 6,6, polyamide 9 and 9,9,polyamide 10 and 10,10, polyamide 11 and 11,11, polyamide 12 and 12,12and their combinations of the 6/9, 6/10, 6/11 and 6/12 type. Preferablythe compositions of the aliphatic esters according to this inventionwith the polyamides are characterised by a content of the plasticizercomprising said aliphatic esters which varies within the range from 0.2to 20% by weight with respect to the total weight of the saidcompositions.

The invention will now be illustrated by a number of examples which areintended to be merely illustrative and not limiting upon it.

EXAMPLES Example 1 Preparation of Aliphatic Esters According to theInvention

A mixture comprising butyl esters and a smaller quantity of linearaliphatic dicarboxylic and monocarboxylic acids obtained by evaporationduring the synthesis of the complex oligomer structures described inExample 1 of WO 2012/085012 was used to prepare the aliphatic esters.100 grams of this mixture having the following composition:

% in moles monobutyl azelate 3.1 dibutyl suberate 2 dibutyl azelate 82.6butyl palmitate 4.1 dibutyl undecandioate 1 butyl stearate 3.1 butylketostearate 4.1 (1:1 mixture of butyl 10-ketostearate and butyl9-ketostearate)were placed together with 19 g of neopentylglycol in a flask heated byan electrical jacket and fitted with a thermometer, a magnetic stirrer,a reflux distillation column and glass rings and a system for regulatingreflux into the flask, a condenser and a flask for collection of thecondensate. The system was heated with stirring at 100° C., and oncecomplete dissolution of the neopentylglycol had been achieved, 0.0223 gof Tyzor TE® were added. The system was then gradually heated to 250°C., distilling from the reaction medium via butanol and water. After thetemperature of 250° C. had been reached, gradual vacuum was applieduntil 20 mbar was reached. On completion of the reaction a condensatecomprising butanol and water was recovered from the condenser.

The aliphatic esters obtained took the form of a clear yellow liquid andwere analysed by HPLC-MS. For the analysis 2 mg of the mixture of esterswere dissolved in 10 ml of acetonitrile and analysed under the followingconditions:

Column: Kinetex 2.6 μm C8 100 Å 100×2.1 mm Eluents:

-   -   (A)=50 mM CH₃COONH₄ with HCOOH pH=4;    -   (B)=CH3CN;        Elution programme

Time (minutes) A (% vol) B(% vol) 0 40 60 30 5 95 50 5 95 55 40 60Flow (ml/min): 0.5Injector volume (μl): 10

Column T (° C.): 40

Mass spectrometer conditions: ESI ionising source (positive ionisation),Sheath gas flow rate (a.u.) 20, Aux gas flow rate (a.u.) 0, SourceVoltage (Kv): 4.5, Capillary Temperature (° C.): 275, Capillary Voltage(V): 28, Tube Lens Voltage (V): 80, Scan: Full scan 150-2000 and350-3500 Da

HPLC-MS characterisation of the said esters revealed the presence of amixture of compounds having the following structure:

R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₄—C(O)—]_(m)—O—R₃

with R₁ and R₃═H, butyl, —CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₇—C(O)—(CH₂)₈—CH₃,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₈—C(O)—(CH₂)₇—CH₃,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₁₄—CH₃,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₁₆—CH₃; R₄ and R₅═C₆ and C₇ and C₉alkylenes, m being between 1 and 10 (mean value=3).

Examples of these esters are:

CH₃—(CH₂)₃—O—C(O)—(CH₂)₇—C(O)—[—O—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₇—C(O)—]₃—O—(CH₂)₃—CH₃

H—O—C(O)—(CH₂)₇—C(O)—[—O—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₇—C(O)—]₃—O—(CH₂)₃—CH₃

H—O—C(O)—(CH₂)₇—C(O)—[—O—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₇—C(O)—]₄—O—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₇—C(O)—(CH₂)₈—CH₃

Examples 2-4

Three mixtures of butyl esters having the following compositions:

Example 2 (% 3 (% 4 (% in moles) in moles) in moles) butyl pelargonate0.00 2.00 6.09 monobuyl azelate 13.29 9.37 9.62 dibutyl suberate 1.210.89 1.19 dibutyl azelate 64.05 45.37 41.48 butyl palmitate 8.16 14.6114.88 dibutyl undecandioate 1.21 0.86 0.81 butyl oleate 0.91 1.50 1.48butyl stearate 5.74 12.09 11.38 butyl ketostearate 5.14 11.19 10.81 (1:1mixture of butyl 10-ketostearate and butyl 9-ketostearate) butylarachidate 0.00 0.49 0.72 butyl behenate 0.30 1.63 1.56were used to prepare three aliphatic esters in the same preparationconditions of Example 1 using the following amounts of neopentylglycol

Example 2 Example 3 Example 4 Mixture of butyl ester (g) 1000 1000 1000Neopentylglycol (g) 242.2 253.3 182.8

HPLC-MS characterisation of the said esters revealed the presence of amixture of compounds having the same general structure of the estersaccording to Example 1 with R₁ and R₃═H, butyl,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₇—C(O)—(CH₂)₈—CH₃,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₈—C(O)—(CH₂)₇—CH₃,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₁₄—CH₃,—CH₂—C(CH₃)₂—CH₂—O—C(O)—(CH₂)₁₆—CH₃; R₄ and R₅═C₆ and C₇ and C₉alkylenes, m being between 1 and 10 (mean value=3 for Examples 2 and 3,=2 for Example 4).

Table 1 herebelow reports the amount of R₁ and/or R₃ groups of theesters according to Examples 1-4 comprising polyols residues esterifiedwith at least one acid selected from stearic acid, palmitic acid,9-ketostearic acid, 10-ketostearic acid and mixtures thereof, asdetermined according to the HPLC-MS analysis as above described in thepresent application.

TABLE 1 % in moles of R₁ and/or R₃ groups comprising polyols % in molesof R₁ and/or R₃ residues esterified with at groups comprising polyolsleast one acid selected from residues esterified with at stearic acid,palmitic acid, least one acid selected from 9-ketostearic acid,9-ketostearic acid, 10-ketostearic acid 10-ketostearic acid Es. 1 25.619.32 Es. 2 54.28 19.67 Es. 3 87.58 41.24 Es. 4 65.01 29.08

Examples 5 and 12 Use as Plasticizers for Polyvinyl Chloride

The plasticising properties of the aliphatic esters according to theinvention were compared with those of a conventional plasticiser,diisononyl phthalate (DINP, marketed by Polynt under the brand nameDIPLAST® NS) and ester of trimellitic acid with a blend of n-octanol andn-decanol (marketed by Polynt under the brand name DIPLAST® TM 8-10/ST).Identical polymer compositions based on a grade of commerciallyavailable polyvinyl chloride (NORVINYL 7102 PVC, marketed by Ineos)which differed only in the type of plasticiser used were prepared forthe purpose. The compositions are shown in Table 2.

TABLE 2 Quantification by weight of the polymer compositions preparedaccording to Examples 5-12 Example 6 Example 11 Example 12 Example 5comparison Example 7 Example 8 Example 9 Example 10 comparisoncomparison (parts by (parts by (parts by (parts by (parts by (parts by(parts by (parts by Material weight) weight) weight) weight) weight)weight) weight) weight) PVC ¹ 100  100  100  100  100  100  100  100 Plasticiser ¹ 50  — 50  — — — — — Plasticiser ² — — — 50  — — — —Plasticiser ³ — — — — 50  — — — Plasticiser ⁴ — — — — — 50  — —Plasticiser ⁵ — 50  — — — — 50  — Plasticiser ⁶ — — — — — — 50 Stabiliser ¹ 1 1 — — — — — — Stabiliser ² 1 1 — — — — — — Stabiliser ³ —— 8 8 8 8 8 8 PVC ¹ = PCV K70 (PVC NORVINYL 7102); Plasticiser ¹ =aliphatic ester prepared according to Example 1; Plasticiser ² =aliphatic ester prepared according to Example 2; Plasticiser ³ =aliphatic ester prepared according to Example 3; Plasticiser ⁴ =aliphatic ester prepared according to Example 4; Plasticiser ⁵ -diisononyl phthalate (DINP); Plasticiser ⁶ = ester of trimellitic acidwith a blend of n-octanol and n-decanol (DIPLAST ® TM 8-10/ST);Stabiliser ¹ = calcium stearate; Stabiliser ² = zinc stearate;Stabiliser ³ = Calcium/Zinc stabilizer (Bareopan MC 8890 KA/S).

The polymer compositions were prepared in a HAAKE RHEOMIX 600 mixeraccording to compound preparation procedure reported in standard ASTMD2538: the individual components were weighed, homogenised by manualmixing and subsequently loaded into the mixer chamber. The followingconditions were used for processing:

-   -   Temperature=150° C. (Examples 5 and 6—comparison) and 170° C.        (Examples 7, 8, 9, 10, 11—comparison, 12—comparison);    -   40 r.p.m.;    -   Mixing time: 7 minutes.

The processing of the polymer compositions mixtures was comparable.

Sheets of thickness 0.25 mm, 1.5 mm and 3.0 mm were compression mouldedfor each polymer compositions so prepared. During moulding the sampleswere moulded at 5000 psi and T=150° C. for 6 minutes (Example 5 and 6)and at 5000 psi and T=170° C. for 6 minutes (Example 7, 8, 9, 10,11—comparison, 12—comparison). The compression moulded sheets were leftto equilibrate for 24 hours at 23° C.±1° C. and 50%±5% RH.

The polymer compositions were then compression moulded 5000 psi andT=150° C. for 6 minutes (Example 5 and 6) and 5000 psi and T=170° C. for6 minutes (Example 7, 8, 9, 10, 11—comparison, 12—comparison)) obtainingsheets of different thickness for each (0.25 mm, 1.5 mm and 3.0 mm). Thecompression moulded sheets were allowed to equilibrate for 24 hours at23° C.±1° C. and 50%±5% RH and were characterised by analysing theirtensile properties, their Shore A hardness and their resistance toextraction in different solvents as well as their properties as afunction of temperature.

Determination of Tensile Properties

Tensile properties were determined in accordance with Standard ASTMD412, using a rate of extension v=500 mm/min. The test samples wereobtained by punching out the sheets of thickness 1.5 mm. A cutting dieaccording to standard ASTM D 412 was used to prepare the samples. Thetensile strength (σ_(b)), the maximum load (σ_(max)), the elongationcorresponding to the tensile strength (ε_(b)), the elongationcorresponding to the maximum load (ε@σ_(max)) and the Elastic Modulusfor an elongation of 100% (E_(100%)), 200% (E_(200%)) and 300%(E_(300%)) were measured for each mixture. The same properties and theweight loss were determined also on the samples after ageing in aventilated oven maintained at 140° C. for 7 days. Before testing, agedsamples were allowed to equilibrate for 24 hours at 23° C.±1° C. and50%±5% RH.

Determination of Shore A Hardness

Shore A hardness was determined according to standard ASTM D2240. Thesamples were obtained by obtaining 3.0 cm×3.0 cm samples from thecompression moulded sheets of thickness 3.0 mm obtained by compressionmoulding. The samples so obtained were stacked to achieve a finalthickness of at least 6.0 mm in accordance with the procedure specifiedin standard ASTM D2240. The Shore A hardness value has been recordedafter 15 seconds from the beginning of the measure.

Resistance to Extraction in Different Solvents

The resistance of the plasticizers to extraction in different solventswas evaluated using the procedure described in standard ASTM D1239. Thesamples were obtained by cutting samples of dimensions 5.0 cm×5.0 cmfrom the compression moulded sheets of thickness 0.25 mm. The followingsolvents were used for the extraction tests:

-   -   Soapy water: distilled water containing 1.0% by weight of        Marseille soap. The soap had been previously dehydrated by        leaving it in a ventilated stove at 105° C. for 60 minutes. The        extraction tests were performed at 40° C. over 24 hours.    -   Oil: sunflower oil having a high oleic acid content (Agripur AP        80). The extraction tests were performed at 40° C. over 24        hours.    -   n-octane: the extraction tests were performed at 23° C. over 24        hours.

On completion of the tests the samples were washed to remove any tracesof possible solvents, dried with a sheet of paper and allowed toequilibrate at 20° C. for 24 hours.

DMTA Analysis

The DMTA analysis were performed using a rotational rheometer TAinstruments Ares G2. The measurements were made by using the torsiongeometry mode with a rectangular sample in a temperature window of from−80° C. to 50° C. with a temperature rate of 3° C./minute. For theanalysis a frequency of oscillation 1 Hz and 0.1% of deformation wasused. A second set of samples was aged in a ventilated oven maintainedat 140° C. for 7 days and the DMTA properties were determined also onthese samples. Before testing, aged samples were allowed to equilibratefor 24 hours at 23° C.±1° C. and 50%±5% RH.

As will be seen from the data shown in Table 3a, the tensile propertiesand Shore A hardness of the PVC mixtures plasticised with aliphaticesters according to the invention (Example 5, 7, 8, 9, 10) are similarto those of the comparison mixtures plasticised using DINP (Example 6and 11—comparison) and using DIPLAST® TM 8-10/ST Example 12—comparison).

TABLE 3a Tensile and Shore A hardness properties of the mixtures σ_(MAX)ε at σMAX σ_(b) ε_(b) E_(100%) E_(200%) E_(300%) Shore (MPa) (%) (MPa)(%) (MPa) (MPa) (%) A Example 5 18.8 365.7 18.8 365.7 8.2 6.5 5.6 76Example 6 - 19.1 348.0 19.1 348.0 10.2 7.4 6.0 82 comparison Example 719.26 313.54 19.26 313.54 10.1 7.56 6.35 77 Example 8 20.60 352.43 20.60352.43 11.78 8.08 6.40 80 Example 9 21.10 361.83 21.10 361.83 12.70 8.176.42 84 Example 10 16.50 287.34 16.50 287.34 9.83 6.94 5.60 78 Example11 - 20.20 330.15 20.20 330.15 12.32 8.18 6.48 82 comparison Example12 - 21.3 245.5 21.3 245.5 14.3 8.75 6.70 90 comparison

As can be seen from the data on Table 3b, the samples containing theesters according to the present invention retain relevant mechanicalproperties after ageing, similarly to DIPLAST® TM 8-10/ST. The polymercomposition plasticized with DINP, instead, has shown a remarkablereduction of the mechanical properties.

TABLE 3b Tensile properties of the mixtures after ageing in a ventilatedoven at 140° C. for 7 days σ_(MAX) ε_(at σMAX) σ_(b) ε_(b) E_(100%)E_(200%) E_(300%) Weight (MPa) (%) (MPa) (%) (MPa) (MPa) (%) loss (%)Example 7 21.45 287.83 21.45 287.83 17.58 10.03 7.20 −8.55 Example 821.05 334.55 21.05 334.55 15.93 9.35 6.85 −4.92 Example 9 21.48 354.9321.48 354.93 15.15 9.15 6.73 −4.22 Example 10 20.80 186.27 20.80 186.2719.47 10.10 n.d.* −11.04 Example 11 - 63.40 1.80 63.40 1.80 n.d.* n.d.*n.d.* −23.37 comparison Example 12 - 19.15 316.43 19.15 316.43 14.088.53 6.28 −0.99 comparison *n.d. = not detectable

As for the tests of resistance to extraction of the plasticizers, Table4 shows the % loss in weight of the test pieces subjected to the testsdescribed above.

TABLE 4 Resistance to extraction in different solvents Soapy water Oiln-octane Example 5 −5.3 −8.1 −10.40 Example 6 - comparison −1.2 −11.1−23.92 Example 7 −5.82 −9.55 −12.09 Example 8 −1.91 −6.52 −9.91 Example9 −2.05 −8.82 −12.83 Example 10 −8.30 −15.15 ,18.99 Example 11 -comparison −1.06 −13.28 −22.08 Example 12 - comparison −0.5 −12.9 −24.5

Considering both the process of preparation and the mechanicalproperties and resistance to extraction by solvents properties of themixtures obtained, the aliphatic esters according to the inventionappear to be wholly equivalent to conventional plasticizers.

With regard to the DMTA analysis, the herebelow tables show the valuesof G′ @ 25° C., G′ @ −25° C., Onset G′, Max G″ and Max Tan (6) for thepolymer compositions of Examples 7-12 as such (Table 5a) and after 7days of ageing in a ventilated oven maintained at 140° C. (Table 5b).

TABLE 5a Ex. 11 - Ex. 12 - Ex. 7 Ex. 8 Ex. 9 Ex. 10 comparisoncomparison G′ @ 25° C. (MPa) 11 25 38 23 27 72 G′ @ −25° C. (MPa) 7601300 950 710 812 650 Max G″ (° C.) −27 −18 −19 −31 −29 −33 Max Tan (δ)(° C.) 12 21 27 18 22 46

TABLE 5b Ex. 11 - Ex. 12 - Ex. 7 Ex. 8 Ex. 9 Ex. 10 comparisoncomparison G′ @ 25° C. (MPa) 83 68 69 173 1210 75 G′ @ −25° C. (MPa)1300 1600 1300 1400 1390 730 Max G″ (° C.) 0 −3 −9 −6 ≈50 −31 Max Tan(δ) (° C.) 34 31 33 45 ≈50 ≈50

Examples 13—Comparison, 14, 15 and 16—Comparison

Example 13 - Example 16 - comparison Example Example comparison (partsby 14 (parts 15 (parts (parts by Material weight) by weight) by weight)weight) PVC ¹ 100 100 100 100 Plasticiser ⁶ 50 — . — Plasticiser ² — 50— . Plasticiser ³ — — 50 — Plasticiser ⁵ — — — 50 Filler ¹ 30 30 30 30Oil ¹ 5 5 5 5 Stabilizer ³ 8 8 8 8 Stabilizer ⁴ 1 1 1 1 PVC ¹ = PCV K70(PVC NORVINYL 7102); Plasticiser ² = aliphatic ester prepared accordingto Example 2; Plasticiser ³ = aliphatic ester prepared according toExample 3; Plasticiser ⁵ - diisononyl phthalate (DINP); Plasticiser ⁶ =ester of trimellitic acid with a blend of n-octanol and n-decanol(DIPLAST ® TM 8-10/ST); Filler ¹ = CaCO₃; Oil ¹ = epoxidised soybeanoil; Stabiliser ³ = Calcium/Zinc stabilizer (Bareopan MC 8890 KA/S);Stabiliser ⁴ =Octadecyl-3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate (Irganox1076, marketed by BASF).

The polymer compositions were prepared in a HAAKE RHEOMIX 600 mixeraccording to standard ASTM D2538: the individual components wereweighed, homogenised by manual mixing and subsequently loaded into themixer chamber. The following conditions were used for processing:

-   -   Temperature=and 170° C.;    -   40 r.p.m.;    -   Mixing time: 7 minutes.

The processing of the polymer compositions mixtures was comparable.

Sheets of thickness 1.5 mm were compression moulded for each polymercompositions so prepared. During moulding the samples were moulded at5000 psi and T=170° C. for 6 minutes. The compression moulded sheetswere left to equilibrate for 24 hours at 23° C.±1° C. and 50%±5% RH.

The polymer compositions were then compression moulded (T=170° C. for 6minutes) obtaining sheets of 1.5 mm thickness for each polymercompositions prepared. The compression moulded sheets were allowed toequilibrate for 24 hours at 23° C. and 55% RH and were characterised byanalysing their tensile properties according to the method abovedisclosed (Tables 6a and 6b).

TABLE 6a Tensile properties of the polymer compositions as such σ_(MAX)ε at σMAX σ_(b) ε_(b) (MPa) (%) (MPa) (%) Example 13 - 15.95 269.7015.95 269.70 comparison Example 14 15.83 309.42 15.83 309.42 Example 1515.14 260.01 15.14 260.01 Example 16 - 17.08 326.58 17.08 326.58comparison

TABLE 6b Tensile properties of the polymer compositions after 7 days ofageing in a ventilated oven maintained at 140° C. Weight σ_(MAX) ε atσMAX σ_(b) ε_(b) loss (MPa) (%) (MPa) (%) (%) Example 13 - 14.84 257.4014.84 257.40 −0.32 comparison Example 14 15.66 250.97 15.66 250.97 −3.52Example 15 15.57 248.06 15.57 248.06 −2.65 Example 16 - 38.00 2.20 38.002.20 −22.28 comparison

1. Polymer compositions comprising at least one thermoplastic polymer,and at least one plasticizer comprising a composition of one or morealiphatic esters having general formula:R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃ in which: R₁ isselected from one or more of the groups consisting of H, linear andbranched saturated and unsaturated alkyl residues of the C₁-C₂₄ type,and polyol residues esterified with C₁-C₂₄ monocarboxylic acids; R₂comprises —CH₂—C(CH₃)₂—CH₂— and C₂-C₈ alkylene groups, and comprises atleast 50% by moles of the said —CH₂—C(CH₃)₂—CH₂— groups; R₃ is selectedfrom one or more of the groups consisting of H, linear and branchedsaturated and unsaturated alkyl residues of the C₁-C₂₄ type, and polyolresidues esterified with C₁-C₂₄ monocarboxylic acids; R₄ and R₅ compriseone or more C₂-C₂₂ alkylenes and comprise at least 50% by moles of C₇alkylenes; m lies between 1 and
 20. 2. Polymer compositions according toclaim 1, in which R₁ is H and R₃ is different from R₁.
 3. Polymercompositions according to claim 1, in which R₂ is the —CH₂—C(CH₃)₂—CH₂—group.
 4. Polymer compositions according to claim 1, in which R₄ and R₅are C₇ alkylenes.
 5. Polymer compositions according to claim 1,comprising from 10 to 80% by weight of the said aliphatic esters. 6.Polymer compositions according to claim 1, in which said one or morethermoplastic polymers are selected from chlorinated vinyl polymers,thermoplastic elastomers and hydroxy acid polyesters.
 7. A method forplasticizing a thermoplastic polymer composition which comprisesincorporating in the thermoplastic polymer composition an aliphaticester having general formula:R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃ in which: R₁ isselected from one or more of the groups consisting of H, linear andbranched saturated and unsaturated alkyl residues of the C₁-C₂₄ type,and polyol residues esterified with C₁-C₂₄ monocarboxylic acids; R₂comprises —CH₂—C(CH₃)₂—CH₂— and C₂-C₈ alkylene groups, and comprises atleast 50% by moles of the said —CH₂—C(CH₃)₂—CH₂— groups; R₃ is selectedfrom one or more of the groups consisting of H, linear and branchedsaturated and unsaturated alkyl residues of the C₁-C₂₄ type, and polyolresidues esterified with C₁-C₂₄ monocarboxylic acids; R₄ and R₅ compriseone or more C₂-C₂₂ alkylenes and comprise at least 50% by moles of C₇alkylenes; m lies between 1 and
 20. 8. Polymer compositions according toclaim 2, in which R₂ is the —CH₂—C(CH₃)₂—CH₂— group.
 9. Polymercompositions according to claim 8, in which R₄ and R₅ are C₇ alkylenes.10. Polymer compositions according to claim 2, in which R₄ and R₅ are C₇alkylenes.
 11. Polymer compositions according to claim 3, in which R₄and R₅ are C₇ alkylenes.
 12. Polymer compositions according to claim 8,comprising from 10 to 80% by weight of the said aliphatic esters. 13.Polymer compositions according to claim 9, comprising from 10 to 80% byweight of the said aliphatic esters.
 14. Polymer compositions accordingto claim 2, comprising from 10 to 80% by weight of the said aliphaticesters.
 15. Polymer compositions according to claim 3, comprising from10 to 80% by weight of the said aliphatic esters.
 16. Polymercompositions according to claim 4, comprising from 10 to 80% by weightof the said aliphatic esters.
 17. Polymer compositions according toclaim 2, in which said one or more thermoplastic polymers are selectedfrom chlorinated vinyl polymers, thermoplastic elastomers and hydroxyacid polyesters.
 18. Polymer compositions according to claim 3, in whichsaid one or more thermoplastic polymers are selected from chlorinatedvinyl polymers, thermoplastic elastomers and hydroxy acid polyesters.19. Polymer compositions according to claim 4, in which said one or morethermoplastic polymers are selected from chlorinated vinyl polymers,thermoplastic elastomers and hydroxy acid polyesters.
 20. Polymercompositions according to claim 5, in which said one or morethermoplastic polymers are selected from chlorinated vinyl polymers,thermoplastic elastomers and hydroxy acid polyesters.